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Genus 4. MARGINELLA, Lamarck. 



Animal ; disc large, thin, widely expanded behind ; mantle ex- 

 tending over the shell in two lobes, by which it is nearly enveloped, 

 sometimes furnished with filaments ; head fiat, small, with a 

 pair of short tentacles, behind which are the eyes ; respiratory 

 siphon cylindrical, very short. 



Shell; ovately oblong or pyriform, emarginated at the base, spire 

 short, more or less depressed ; aperture oblong, often equalling 

 the length of the shell ; columella plaited nearly equally ; outer 

 lip rolled back and solidified. 



Eegarding the general aspect of the Marginclla, it is not surprising that 

 Linnaeus should have referred them to the genus Voluta ; the shell differs, 



H 2 



